Catalytic hydrogenation is a fundamental reaction in chemistry, and is used in a large number of chemical processes. Catalytic hydrogenation of ketones and aldehydes are useful and indispensable processes for the synthesis of alcohols, which are valuable end products and precursor chemicals in the pharmaceutical, agrochemical, flavor, fragrance, material and fine chemical industries.1 
To achieve a catalytic hydrogenation transformation in the reduction of ketones and aldehydes, molecular hydrogen (H2) is used. However, for the hydrogenation process to proceed, a catalyst or catalytic system is needed to activate the molecular hydrogen.
Noyori and co-workers developed the versatile RuCl2(PR3)2(diamine) and RuCl2(diphosphine)(diamine) hydrogenation catalyst system that are highly effective for the hydrogenation of ketones.2 It was subsequently discovered that the Noyori catalysts were effective for the reductive hydrogenation of imines to amines.3 
It was also determined that ruthenium aminophosphine complexes of the type RuCl2(aminophosphine)2 and RuCl2(diphosphine)(aminophosphine) are also very effective catalysts for the hydrogenation of ketones, aldehydes and imines, including the preparation of chiral compounds.4 Hence, these catalysts are versatile alternatives to the Noyori-type catalysts.
Currently, the availability of chiral and achiral aminophosphine ligands are severely limited which restricts the development and exploitation of RuCl2(aminophosphine)2 and RuCl2(diphosphine)(aminophosphine) catalysts in catalytic hydrogenation processes. The few reported syntheses of aminophosphine ligands are either low yielding or involve the use of aziridines.5 
Hence, there remains a need for a facile synthesis of chiral and achiral aminophosphine ligands in high yields and purity, and suitable for large scale applications.